Have fun adjusting the needle when flying real fast. You will have your hands full. I think there used to be an FAI speed class with no line size, as long as you did the pull test. Years ago, there were line groupers that really let the speeds go up. Of course they were outlawed the next year. The US events always raise the line size and length whenever the record goes over 200 MPH. With the line sizes from the 1960s I am sure there would be some great speeds with the modern engines. Any motor over a .29 is not allowed a pipe now, that slows things a lot. I have not flown speed for maybe 20 years because of no good paved circle. Maybe I found one in Flint Mi? I'll have to see how that goes. $13 to cross the border, deal with the Gestoppo, 2 hr. drive... The guys in the club seem pretty cool.